The invention relates to an apparatus for storage of substrate portions having a self adhesive layer covered by a carrier layer which are place in bags wherein protection from adhesive bonding with packaging material of the bags is provided by elevations on the carrier layer which function as spacers with respect to the bag.
The manufacture and use of sheet-like self-adhesive substrate portions formed of a substrate having an adhesive layer covered by a carrier layer is known. After they have been manufactured, there is the necessity to protect the substrate portions from loss of active material, for example as a result of evaporation, from the time at which they are stored until they are used. This is preferably achieved in that the self-adhesive substrate portions containing the active material, after their self-adhesive area has been covered, for the purpose of protection, wherein the carrier layer is a detachable carrier or protective layer, are sealed into a bag which encloses the substrates on all sides and is made of a material which is impermeable to the vapour phase. The carrier layer preferably projects beyond the self-adhesive area, which means that pulling off the carrier or protective layer is made easier.
One disadvantage of this package results from the fact that, during the storage of these substrate portions packed in this way, cold flow of the self-adhesive causes adhesive to emerge in the region around the substrate portion, and to cause the substrate to bond adhesively to the packaging material, as a result of which the removal of laminate of the packaging material, in the case of a bag packaged which is to be opened on only one side at a time of use, is made considerably more difficult or even impossible.
In these self-adhesive substrate portions, it is known to introduce an incision or a common tearing aid, for example in the form of a weakening, embrittlement or perforation, into the carrier layer, which makes the tearing open and detachment of the carrier layer easier or at all possible with a reasonable effort, and therefore aids the application of the self-adhesive substrate portions to the skin.
One disadvantage of this design of the package results from the fact that, during the storage of the substrate portions, cold flow in the region of the cut or weakening line causes self-adhesive components to emerge, which results in the substrate disadvantageously bonding adhesively to the surrounding packaging bag material. As a result, removing the laminate from the package opened on the one side is made considerably more difficult, or is even made impossible without damage.
EP 0 405 393 describes an apparatus for increasing the storage stability of sheet-like substrate portions which are equipped with a self adhesive and packed in bags and whose self-adhesive area is protected by a carrier layer projecting beyond it at least to some extent. Arranged in the carrier layer are space-maintaining elevations, specifically on the carrier layer, as spacers between the carrier layer and bag.
DE-A-19 36 607 discloses a rapid wound dressing which comprises a carrier strip provided-with a self-adhesive layer, a wound pad applied thereto to cover the wound directly in the form of a cushion-like structure made of gauze, cellulose, fibrous fleece or similar material, and a protective material arranged above it. This last layer is designed as a sheet-like piece, which can be divided along a predetermined line. This dividing line is formed by a weakening of the material, such as a perforation or incisions.
Starting from the abovementioned prior art, the present invention is based on the object of specifying an apparatus for increasing a storage stability of substrate portions which are provided with a self-adhesive layer and are packed in bags. The apparatus prevents adhesive bonding of the substrate to the packing areas of the bag, even given comparatively long storage and in spite of cold flow of the self adhesive, and provides for the use of the unimpeded, easy removal of the substrate from the pack, which is opened on only one side.
In order to achieve the object, the present invention provides elevations on a side of the carrier layer on which is the substrate and elevations on an opposite side of the carrier layer wherein the elevations are designed as spacers to separate the carrier layer from the bag.
The spacers arranged on the side of and the opposite side of the carrier layer in accordance with the present invention provide an advantage, on the one hand, of a very uncomplicated type of package and, on the other hand, reliably prevent adhesive bonding between substrate and package, even during a comparatively long storage of sandwich-type laminates having an amorphous adhesive layer tending to cold flow between two solid layers. In particular in the presence of a detachment aid designed as a perforation line in the form of an incision or perforation in the carrier layer. The present invention eliminates the acute risk of adhesive bonding between the latter and the packaging material resting on it in an easy way and with simple means if, according to the present invention, there are space-maintaining elevations along the cut or weakening line.